Testing instrument for analyzing liquid sample

ABSTRACT

A test device  1  for analyzing a specific component in a test solution with a reagent by allowing the solution introduced via a feed opening  4  to react with the reagent maintained in a predetermined position in a capillary tube  3  having the opening  4  and an air outlet  5.  The tube is provided with two hydrophilic regions  31,33  and a hydrophobic region  32.  The region  31  transfers the solution from the opening  4  to the reagent. The region  33  is delimited to a predetermined area maintaining the reagent. The region  32  separates the region  31  from the region  33.  The reagent and the solution are applied in predetermined amounts to the region  33.  A measuring device need not previously measure the solution. The device is useful as an analytical device for rapid and easy analysis, and can be produced in a less number of steps because the reagent can be fixed by merely applying it onto a predetermined position.

This application is a 371 of PCT/JP98/01010 filed of Mar. 11, 1998.

TECHNICAL FIELD

The present invention relates to a test device for analysis ofcomponents contained in liquid samples, particularly aqueous solutionssuch as blood and urine.

BACKGROUND ART

A simple test device for analysis of a liquid sample by reaction with areagent generally utilizes capillary action for introduction or transferof a sample to a site for reaction with the reagent in the test device.As this test device, there are the type of device where a reagentapplied onto a capillary tube comes to be dissolved in a sample and thetype of device where a sample penetrates into a reagent layer providedon a capillary tube.

As an example of the former, JP-A63-274839 describes a test devicecomprising a lower stretching member also serving as a shaft and anupper member containing a reagent while forming a capillary tube via aspacer with said lower member. As an example of the latter, JP-A4-188065 describes an analytical device comprising a carrier, a reagentlayer sealed to the carrier, and a cover which while covering thereagent layer, is fixed so as to form a capillary chamber with thecarrier, said cover having a sample feed opening and an air outlet.

However, in the type of device where a reagent comes to be dissolved ina sample, such as in the test device described in JP-A 63-274839, theconcentration of a reaction solution should be accurately defined, so asample to be fed should previously be introduced into a vessel with aknown volume such as pipette. Further, in the type of device where asample penetrates into a reagent layer, such as in the test devicedescribed in JP-A 4-188065, the reagent should be contained in a paperor a film separate from a capillary tube and then fixed to the capillarytube in order to maintain the volume of the reagent layer.

Accordingly, the object of the present invention is to provide a testdevice which can easily measure a predetermined amount of a sample andsimultaneously analyze the sample without pipetting the sample intoanother vessel or separately preparing a reagent layer for fixing thesample.

DISCLOSURE OF THE INVENTION

To achieve the object, the test device of the present invention is atest device for analyzing a specific component in a test solution with areagent by allowing the test solution introduced via a test solutionfeed opening to react with the reagent maintained in a predeterminedposition in a capillary tube having the feed opening and an air outlet,said capillary tube comprising:

a first hydrophilic region for transferring the test solution from thetest solution feed opening to the reagent,

a second hydrophilic region having a predetermined area maintaining thereagent, and

a hydrophobic region which separates the first hydrophilic region fromthe second hydrophilic region and communicates with the air outletwithout passing through the first and second hydrophilic regions.

According to this test device, a test solution introduced via the testsolution feed opening advances by capillary action through the firsthydrophilic region to the reagent. Simultaneously, the air in thecapillary tube is pushed out and discharged from the air outlet. Oncethe test solution reaches the hydrophobic region, its transfer isprevented transiently by the hydrophobic region. Then, when externalforce is applied to the test device, the test solution pass through thehydrophobic region to transfer to the second hydrophilic region.

Because the area of the second hydrophilic region is constant, theamount of the test solution maintained therein is determined by its areaand the internal diameter of the capillary tube. When the test solutionpasses the hydrophobic region to transfer to the second hydrophilicregion, the test solution remaining on the hydrophobic region or thesolution which cannot be maintained on the second hydrophilic region isremoved by repulsion by the hydrophobic region. Accordingly, it is notnecessary to pipette the test solution previously into a vessel having aknown volume or to maintain the reagent in a layered predetermined area.Further, because the region maintaining the reagent is hydrophilic, thereagent can be fixed to the second hydrophilic region by merely applyingit. By reaction between a predetermined amount of the maintained testsolution and the reagent, a specific component in the test solution canbe analyzed highly accurately.

External force applied to permit the test solution to pass through thehydrophobic region includes e.g. instantaneous vibration or centrifugalforce by shaking the test device by the hand of an operator, suctionforce by suction through the air outlet, and pressurization through thefeed opening.

The air outlet is preferably a penetration hole formed in such adirection that it intersects the capillary tube. By forming thepenetration hole in this way, the capillary tube can be formed into atube where excluding the penetration hole, the test solution feedopening only is open, and the overflow of the test solution maintainedin the second hydrophilic region can be prevented. The angle at whichthe penetration hole intersects the capillary tube at the side of thefirst hydrophilic region is preferably an acute angle. By thisconstitution, when the test solution is transferred by external force tothe second hydrophilic region, it can stop flowing from the penetrationhole, thus preventing biohazard.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the test device in the first embodiment.

FIG. 2 is a plan view of the test device in the first embodiment.

FIG. 3 is a sectional view of the test device in the first embodiment.

FIG. 4 is a plan view of the test device in the second embodiment.

FIG. 5 is a sectional view of the test device in the second embodiment.

FIG. 6 is a plan view of the test device in the third embodiment.

FIG. 7 is a plan view of a test device in a comparative example to thethird embodiment.

FIG. 8 is a plan view for explaining an evaluation method in Example 1.

FIG. 9 is a plan view of the test device in the fourth embodiment.

FIG. 10 is a sectional view of the test device in the fourth embodiment.

FIG. 11 is a sectional view of a test device in a comparative example tothe fourth embodiment.

FIG. 12(A) is a plan view of a capillary tube for explaining anevaluation method in Example 2, and

FIG. 12(B) is a plan view for a comparative example to Example 2.

FIG. 13 is a plan view of the test device in the fifth embodiment.

FIG. 14 is a sectional view of the test device in the fifth embodiment.

FIG. 15 is a plan view of the test device in the sixth embodiment.

FIG. 16 is a plan view of a test device in a comparative example to thesixth embodiment.

FIG. 17 is a plan view of a test device in another comparative exampleto the sixth embodiment.

FIG. 18 is a plan view of the test device in the seventh embodiment.

FIG. 19 is a plan view of the test device in the eighth embodiment.

FIG. 20 is a plan view of the test device in the ninth embodiment.

FIG. 21 is a plan view of a first type of transfer of a test solution ina capillary tube.

FIG. 22 is a plan view of a second type of transfer of a test solutionin a capillary tube.

FIG. 23 is a plan view of a third type of transfer of a test solution ina capillary tube.

FIG. 24 is a perspective view of the test device in the tenthembodiment.

FIG. 25 is a sectional view in XXV—XXV of FIG. 24.

FIGS. 26(A), (B) and (C) are sectional views of the test device at thepreparative stage, corpuscle removing stage and plasma volume regulatingstage respectively in the eleventh embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

The test device of the present invention in the first embodiment isshown in the perspective view of FIG. 1, the plan view of FIG. 2 and thesectional view of FIG. 3.

Test device 1 is provided with rectangular parallelepiped main body 2.The main body 2 is composed of three transparent plates where the middleplate is manufactured into a frame, and the hollow 3 which is long andnarrow in the lengthwise direction, surrounded by the frame and theupper and lower plates, functions as a capillary tube. The upper platein the main body 2 is provided with a feed opening 4 communicating withone end of the hollow 3. The internal surface of the hollow 3 consistsof the first hydrophilic region 31 continuous with the feed opening 4and modified to be hydrophilic, the hydrophobic region 32 continuoustherewith, and the second hydrophilic region 33 continuous therewith,and the hollow 3 is blocked at the back of the second hydrophilic region33. The main body 2 is provided with the penetration hole 5 forpermitting the hydrophobic region 32 to communicate with the outsidewithout passing through the hydrophilic regions 31 and 33, and thepenetration hole 5 is provided in such a direction that it intersectswith the hollow 3 and forms an acute angle with the first hydrophilicregion. A reagent (not shown) is applied to the second hydrophilicregion 33.

The method of manufacturing the test device 1 is e.g. as follows. Threerectangular plates made of ABS are prepared. ABS is inherentlyhydrophobic. In the first plate, regions on which the hydrophilicregions 31 & 33 are to be formed are irradiated with UV rays from alow-pressure mercury lamp as a light source. The portions thusirradiated have been modified to be hydrophilic. The second plate ismanufactured into a frame and provided with the penetration hole 5. Thethird plate is provided with the feed opening 4, and the predeterminedportions are modified to be hydrophilic in the same manner as in thefirst plate. After a reagent (not shown) is applied to the secondhydrophilic region 33, the three plates are laminated and fixed. Thetest device is thus completed. Further, a plate made of an originallyhydrophilic material may be used in place of the plate made of ABS. Inthis case, the test device 1 can be produced in the same manner byapplying a hydrophobic coating such as alkoxy silane onto thepredetermined portions on a hydrophilic plate such as a glass plate.There is no necessity for separately forming a reagent in either case,unlike the prior art.

The procedure of analyzing a liquid sample by the test device 1 is asfollows: Collected blood itself or blood subjected tocorpuscle-separating treatment, in a slightly larger amount than theoptimum amount, is pushed against the feed opening 4. The blood whilewetting the first hydrophilic region 31 is transferred by capillaryaction toward the second hydrophilic region 33, but is prevented frombeing transferred on the way by the hydrophobic region 32. If collectedblood itself is used as a sample, a pretreatment means such as corpuscleseparating membrane etc. may be provided on the way of the firsthydrophilic region 31. Then, the side of the main body 2 (right side inthe drawing) is tapped lightly. By this external force, the blood withwhich the first hydrophilic region 31 is filled is transferred via thehydrophobic region 32 to the second hydrophilic region 33.Simultaneously, the air in the space surrounded by the secondhydrophilic region 33 is removed through the penetration hole 5. Theblood initiates reaction with the reagent. The hydrophobic region 32 isnot wetted by blood, so the amount of blood to be filled in the secondhydrophilic region delimited by the inner wall of the capillary tube andthe hydrophobic region 32 is always constant. Accordingly, the blood canbe analyzed quantitatively with high accuracy. In addition, the mainbody 2 is transparent so the blood can be analyzed rapidly with anoptical means.

For the following reason, it is preferable that the penetration hole 5as an air outlet is arranged preferably in a position apart by c=0.2 mmor more from the boundary portion between the secondary hydrophilicregion 33 and the hydrophobic region 32. The hydrophobic region, once atest solution is passed therethrough, can be rendered slightlyhydrophilic by the action of the test solution. Because the hydrophobicregion and the secondary hydrophilic region are continuous on the samesurface, a test solution introduced into the second hydrophilic regionmay form a meniscus at the boundary with the hydrophobic region.Accordingly, if this boundary portion is too close to the air outlet,the meniscus is not stopped by the hydrophobic region and thus bindsdirectly to the air outlet, thus permitting the test solution to flowout through the air outlet.

Second Embodiment

Now, the test device in the second embodiment is shown in the plan viewof FIG. 4 and in the sectional view of FIG. 5. This test device 6 hasthe same structure as in the first embodiment except that it is notprovided with the penetration hole 5, the hollow 7 is also open in theopposite side to the feed opening 8, the opening 9 has an exhaustfunction in place of the penetration hole 5, the hydrophobic regions 72and 74 in the hollow 7 are separated into two positions between whichthe second hydrophilic region 73 is sandwiched.

In the case of analysis by this test device 6, the air in the hollow 7is removed through the opening 9 as the test solution advances due tocapillary action. The hydrophobic regions 72 and 74 are not wetted byliquid, so the amount of blood filled in the second hydrophilic region73 delimited by the inner wall of the capillary tube and the hydrophobicregions 72 and 74 is always constant. Because air is removed from theopening 9 which is located at a position extending from the secondhydrophilic region 73, the test solution advances rapidly.

Third Embodiment

The test device of the present invention in the third embodiment isshown in the plan view of FIG. 6. In this embodiment, the capillary tubeis bent between the first hydrophilic region and the hydrophobic region.Further, assuming that the air outlet extends without bending the firsthydrophilic region at the boundary with the hydrophobic region, it isarranged at a position which is not the imaginary extending portion.Hereinafter, the test device is described in detail by reference to thedrawings.

The test device 11 is provided with the rectangular parallelepiped mainbody 12. The main body 12 is composed of three transparent plates, wherethe middle plate is manufactured into a frame, and the hollow 13 whichis long and narrow in the lengthwise direction, surrounded by the frameand the upper and lower plates and bent at two positions, acts as acapillary tube. The hollow 13 begins at one end of the main body 12 andis blocked on the way without reaching the other end. In this example,its beginning portion serves as the feed opening 14.

The inside of the hollow 13 is composed of the first hydrophilic region131, the hydrophobic region 132, and the second hydrophilic region 133.The first hydrophilic region 131 extends from the feed opening 14 to thefirst bending portion, the hydrophobic region 132 extends from the firstto second bending portions, and the hollow 13 is blocked at the back ofthe second hydrophilic region 133. The hollow 13 bends to the right atthe first bending point and to the left at the second bending point inthe direction to which a sample advances. In the present invention, therelationship between the angel of the first bending point, particularlythe angle of the outer peripheral side expressed as α in FIG. 1, and thewidth of the hollow 13 is important. That is, assuming that the firsthydrophilic region 131 extends without being bent at the boundary withthe hydrophobic region 132, the imaginary extending portion is designedso as to overlap with the second hydrophilic region 133.

The main body 12 is provided with the penetration hole 15 permitting thehydrophobic region 132 to communicate with the outside without passingthrough both hydrophilic regions 131 and 133. This penetration hole 15functions as an air outlet. The first bending point is provided at theinner peripheral side with the penetration hole 15. A reagent (notshown) is applied to the second hydrophilic region 133.

The method of manufacturing the test device 11 is essentially the sameas in the first embodiment. However, polystyrene (PS) is used in placeof ABS as the material.

The procedure of analyzing a test sample by the test device 11 is alsothe same as in the first embodiment. However, a part of blood flowingfrom the first hydrophilic region 131 to the secondary hydrophilicregion 133 is contacted with the side wall of the hydrophobic region132. While its direction is changed by the counter force to forciblytransfer the air in the hydrophobic region 132 to the penetration hole15, the blood is transferred to the second hydrophilic region 133.Accordingly, the air is removed easily as compared with the firstembodiment.

The degree of bending of the capillary tube is not limited. Thecapillary tube may also be bent smoothly or may be bent such that thefirst hydrophilic region and the hydrophobic region intersect. However,the capillary tube is preferably bend to such an extent that saidimaginary extending portion overlaps with the second hydrophilic region.By doing so, the whole of the test solution flowing from the firsthydrophilic region is prevented from being splashed on the side wall ofthe hydrophobic region.

EXAMPLE 1

The test device 11 in the form shown in FIG. 1 was prepared where thewidth and height of the hollow 13 were 3 mm and 0.2 mm respectively, thedepth “a” of the second hydrophilic region 133 was 3 mm, the length “b”of the hydrophobic region 132 was 5 mm, the hollow 13 was bent at 30° tothe right at the first bending point and at 30° to the left at thesecond bending point in the direction to which a sample advances.

Human plasma or serum (hereinafter referred to as human plasma) wasintroduced as the test solution via the feed opening 14 into the testdevice 11, and external force was applied to transfer the test solutionto the second hydrophilic region 133. For comparison, the test deviceR11 having the same shape and quality as the test device 11 except thatthe hollow was not bent as shown in FIG. 7 was prepared, and the testsolution was transferred to the second hydrophilic region 133′ in thesame manner. The ratio of inclusion of air bubble (FIG. 8) in the testsolution maintained in the second hydrophilic regions 133 and 133′ wasevaluated. The number of test devices was 20 for each of the testdevices 11 and R11. Three minutes later, the maintained test solutionwas removed by means of a micro-syringe, and its amount was measured toevaluate the maintenance accuracy. These evaluation results are shown inTable 1.

TABLE 1 (n = 20) Test Ratio of inclusion of Maintenance accuracy devicebubble (%) (CV %) 11  0 2.5 R11 25 6.1

As shown in Table 1, when the test solution is transferred to thereagent-maintaining portion, the test solution can be transferredquantitatively without introducing bubbles into the test solution,according to the test device in this example.

Fourth Embodiment

In the first to third embodiments described above, the hydrophobicregion is continuous on the same face with the second hydrophilicregion. In this structure, as shown in the first embodiment, the testsolution which entered into the second hydrophilic region may form ameniscus in the boundary with the hydrophobic region. If this meniscusis convex, there is no problem. However, if it is concave and thedistance “c” (FIG. 2) is unintentionally inadequate, there is apossibility that the test solution goes along the wall of the tube toflow gradually from the air outlet. Accordingly, it becomes difficult toquantitatively maintain the test solution in the second hydrophilicregion.

Accordingly, in the fourth embodiment, a groove poorer in wettabilitythan the second hydrophilic region is made at the boundary between thehydrophobic region and the second hydrophilic region. Thus, the groovefurther stresses the difference in wettability between the two regionsto regulate the meniscus. The test device in the fourth embodiment isshown in the plan view of FIG. 9 and in the sectional view of FIG. 10.Hereinafter, the test device is described in detail by reference to thedrawings.

The test device 21 is provided with the rectangular parallelepiped mainbody 22. The main body 22 is composed of three transparent plates, wherethe middle plate is manufactured into a frame, and the hollow 23 whichis long and narrow in the lengthwise direction, surrounded by the frameand the upper and lower plates, acts as a capillary tube. The hollow 23begins at one end of the main body 22 and is blocked on the way withoutreaching the other end. In this example, its beginning portion serves asthe feed opening 24.

The inside of the hollow 23 is composed of the first hydrophilic region231, the hydrophobic region 232 and the second hydrophilic region 233 inthis order from the side of the feed opening 24. The hollow 23 isblocked at the back of the second hydrophilic region 233. The hollow 23is provided with the grooves 26 facing up and down around the squarehydrophobic region 232.

The main body 22 is provided with the penetration hole 25 permitting thehydrophobic region 232 to communicate with the outside without passingthrough both hydrophilic regions 231 and 233. The penetration hole 25functions as an air outlet. A reagent (not shown) is applied to thesecond hydrophilic region 233.

The method of manufacturing the test device 21 is essentially the sameas in the first embodiment. However, two plates made of polystyrene (PS)and one plate made of polyvinyl chloride (PVC) are used in place ofthree plates made of ABS as the material. By irradiation with UV rays,the predetermined regions are modified to be hydrophilic. Then, thegrooves 26 are made with a knife around the portion which will form thehydrophobic region 232 on the first and second PS plates. Awater-repellent agent such as dimethyl polysiloxane is applied to theportion surrounded by the grooves 26. The presence of the grooves 26prevents the water-repellent agent from flowing into the hydrophilicregion. After a reagent (not shown) is applied to the second hydrophilicregion 233, the three plates are laminated and fixed. The test device isthus completed.

The procedure of analyzing a liquid sample by the test device 21 is alsothe same as shown in the first embodiment. However, the grooves 26 aremade at the boundary between the hydrophobic region 232 and the secondhydrophilic region 233, so the amount of blood to be filled in thesecond hydrophilic region 233 is always more constant than in the firstembodiment. Accordingly, the sample can be quantitatively analyzed withhigh accuracy.

Said grooves are made preferably on the whole periphery of thehydrophobic region including the boundary with the second hydrophilicregion. The reason for this is as follows: Whether a certain region ishydrophilic or hydrophobic is relatively determined. In the method ofaltering wettability on a capillary tube, there are cases where acapillary tube is rendered more hydrophilic or more hydrophobic thanoriginal. In the present invention, at least two hydrophilic regions andat least one hydrophobic region should be formed in a capillary tube.Accordingly, there are the following 3 combinations: (1) the hydrophobicregion remains original while the region to be rendered hydrophilic ismodified to be more hydrophilic than original; (2) the region to berendered hydrophobic is modified to be more hydrophobic than originalwhile the hydrophilic region remains original; and (3) the region to berendered hydrophobic is modified to be more hydrophobic than originalwhile the region to be rendered hydrophilic is rendered more hydrophilicthan original. The modification for conferring hydrophilicity isconducted by physical means such as UV irradiation, whereas themodification for conferring hydrophobicity is usually conducted byapplying a water-repellent agent. Said grooves assume the role ofpreventing the water-repellent agent applied onto the hydrophobic regionfrom flowing to the hydrophilic region. Accordingly, the boundarybetween the hydrophobic and hydrophilic regions can be made definite byproviding the whole periphery of the hydrophobic region with thegrooves.

If the diameter of said capillary tube provided with the grooves is 100to 800 μm in the depth direction of the groove, the depth of the grooveis preferably {fraction (1/10)} to ½ relative to the diameter of thecapillary tube.

Fifth Embodiment

Now, the test device in the fifth embodiment is shown in the plan viewof FIG. 13 and in the sectional view of FIG. 14. The test device 29 hasthe same structure as in the fourth embodiment except that (1) it is notprovided with the penetration hole 25, (2) the hollow 27 is also open inthe opposite side to the feed opening 278, and the opening 275 has anexhaust function in place of the penetration hole 25, (3) thehydrophobic regions 272 and 274 in the hollow 27 are separated into twopositions between which the second hydrophilic region 273 is sandwiched,and (4) accordingly the groove 262 is also made at the boundary betweenthe second hydrophilic region 273 and the second hydrophobic region 274.

In the case of analysis by this test device 29, the air in the hollow 27is removed from the opening 275 as a test solution advances due tocapillary action. The hydrophobic regions 272 and 274 are not wetted byliquid. Further, the grooves 276 are made in the boundary between thehydrophobic regions 272, 274 and the second hydrophilic region 273, sothe amount of blood to be filled in the second hydrophilic region 273 isalways constant. Because air is removed from the opening 275 which islocated at a position extending from the second hydrophilic region 273,the test solution advances rapidly.

EXAMPLE 2

The test device 21 in the form shown in FIGS. 9 and 10 was preparedwhere the width and height of the hollow 23 were 3 mm and 500 μmrespectively, the depth of the second hydrophilic region 233 was 3 mm,and the depth of the groove 26 was 130 μm.

Human plasma was introduced as the test solution via the feed opening 24into the test device 21, and by application of external force, the testsolution was transferred to the second hydrophilic region 233. Forcomparison, the test device 21′ having the same shape and quality as thetest device 21 except that as shown in FIG. 11, it was not provided withthe groove 26 was prepared, and the test solution was transferred to thesecond hydrophilic region 233′ in the same manner. Whether the testsolution maintained in the second hydrophilic regions 233 and 233′formed the meniscus shown in FIG. 12(A) or the linear interface shown inFIG. 12(B) in the boundary between the hydrophobic regions 232 and 232′was observed. The number of test devices was 20 for each of the testdevices 21 and 21′.

Three minutes later, the maintained test solution was removed by meansof a micro-syringe, and its amount was measured to evaluate themaintenance accuracy. These evaluation results are shown in Table 2. InTable 2, the numerical number in item A is the number of test devicesforming the meniscus shown in FIG. 12(A), and the numerical number initem B is the number of test devices forming the liner interface shownin FIG. 12(B).

TABLE 2 (n = 20) Test Maintenance accuracy device A B (CV %) 21 0 20 0.921′ 20 0 3.4

As shown in Table 2, when the test solution is transferred to thereagent-maintaining portion, the test solution can be maintainedquantitatively without forming a meniscus, according to the test devicein this example.

Sixth Embodiment

As described in the fourth embodiment, the test solution introduced intothe second hydrophilic region will form a meniscus in the boundary withthe hydrophobic region. If this meniscus is large, the test solutioncannot be quantitatively maintained in the second hydrophilic regioneven if the second hydrophilic region is provided with excellentdimension accuracy.

Thus, in the sixth embodiment, the width “d” of the capillary tube inthe boundary portion between the hydrophobic region and the secondhydrophilic region is made narrower than the width “D” of the capillarytube in the second hydrophilic region. Accordingly, when the area of thesecond hydrophilic region is constant, the meniscus formed in the testdevice in this example is smaller than the meniscus formed in the testdevice with a capillary tube having uniform width. The test device inthe sixth embodiment is shown in the plan view of FIG. 15. Hereinafter,the test device is described in detail by reference to the drawings.

The test device 31 is provided with the rectangular parallelepiped mainbody 32. The main body 32 is composed of three transparent plates, wherethe middle plate is manufactured into a frame, and the hollow 33 whichis long and narrow in the lengthwise direction, surrounded by the frameand the upper and lower plates, acts as a capillary tube. The hollow 33begins at one end of the main body 32 and is blocked on the way withoutreaching the other end. In this example, the beginning portion serves asthe feed opening 34.

The inside of the hollow 33 is composed of the first hydrophilic region331, the hydrophobic region 332 and the second hydrophilic region 333 inthis order from the side of the feed opening 34. The width of the hollow33 from the feed opening 34 to the hydrophobic region 332 is constant,whereas the width of the hollow 33 in the second hydrophilic region 333continuous with the hydrophobic region 332 is increased in the widthdirection. Then, the hollow 33 is blocked at the back of the secondhydrophilic region 333. Accordingly, the first hydrophilic region 331and the hydrophobic region 332 are rectangular, and the secondhydrophilic region 333 only is trapezoid.

The main body 32 is provided with the penetration hole 35 for permittingthe hydrophobic region 332 to communicate with the outside withoutpassing through both the hydrophilic regions 331 and 333. Thepenetration hole 35 is connected to the hydrophobic region 332 in aposition apart from the boundary between the hydrophobic region 332 andthe second hydrophilic region 333 and extends to the side of the mainbody 32, so as to be apart from the second hydrophilic region 333. Thispenetration hole 35 functions as an air outlet. A reagent (not shown) isapplied to the second hydrophilic region 333.

The method of manufacturing the test device 31 is essentially the sameas in the first embodiment except that PS is used in place of ABS as thematerial.

The procedure for analyzing a liquid sample by the test device 31 is asshown in the first embodiment.

However, unlike the first embodiment, the width of the boundary portionbetween the hydrophobic region 332 and the second hydrophilic region 333is narrower than the width of the second hydrophilic region 333, so themeniscus formed in the boundary portion is small. Accordingly, theamount of blood to be filled in the second hydrophilic region 333 isalways more constant than in the first embodiment, and thus the bloodcan be analyzed quantitatively with high accuracy.

Said air outlet is arranged preferably at a position apart by c=0.2 mmor more from the boundary portion between the secondary hydrophilicregion and the hydrophobic region. By doing so, the meniscus iscertainly stopped by the hydrophobic region without binding directly tothe air outlet, as mentioned in the first embodiment. As a result, theoutflow of the test solution through the air outlet is prevented.

Seventh Embodiment

Now, the test device in the seventh embodiment is shown in the plan viewof FIG. 18. This test device 39 has the same structure as in the sixthembodiment except that (1) it is not provided with the penetration hole35, (2) the hollow 37 is also open in the opposite side to the feedopening 378, and the opening 375 has an exhaust function in place of thepenetration hole 35, (3) the hydrophobic regions 372 and 374 in thehollow 37 are separated into two positions between which the secondhydrophilic region 373 is sandwiched, and (4) accordingly the width ofthe capillary tube at the boundary portion between the secondhydrophilic region 373 and the second hydrophobic region 374 is narrowerthan the width of the capillary tube in the second hydrophilic region373.

In the case of analysis by the test device 39, the air in the hollow 37is removed from the opening as the test solution advances due tocapillary action. The hydrophobic regions 372 and 374 are not wetted byliquid. In addition, the width of the boundary portion between thehydrophobic regions 372, 374 and the second hydrophilic region 373 isnarrow, so the amount of blood filled in the second hydrophilic region373 is always constant. Because air is removed from the opening 375which is located at a position extending from the second hydrophilicregion 373, the test solution advances rapidly.

EXAMPLE 3

The test device 31 in the form shown in FIG. 15 was prepared where thewidth “d” and the height of the hollow 33 from the feed opening 34 tothe second hydrophilic region 333 were 3 mm and 500 μm respectively, thedepth of the second hydrophilic region 333 was 3 mm, and the maximumwidth “D” of the second hydrophilic region 333 was 5 mm. The penetrationhole 35 was arranged in a position apart by 2 mm from the boundaryportion between the hydrophobic region 332 and the second hydrophilicregion 333.

Human plasma was introduced as a test solution via the feed opening 34to this test device 31, and by applying external force, the testsolution was transferred to the second hydrophilic region 333. Forcomparison, the test device 31′ having the same shape and quality as thetest device 31 except that the width of the hollow 33 is equally 3 mm asshown in FIG. 16 was produced, and the test solution was transferred inthe same manner to the second hydrophilic region 333′. Further, the testdevice 31″ having the same shape and quality as the test device 31′except that as shown in FIG. 17, the penetration hole is formed at theboundary region between the hydrophobic region 332 and the secondhydrophilic region 333 was produced, and the test solution wastransferred in the same manner to the second hydrophilic region 333″.The number of devices was 20 for each of the test devices 31, 31′ and31″.

Three minutes later, the test solution maintained in the secondhydrophilic region in each device was removed by means of amicro-syringe, and its amount was measured to evaluate the maintenanceaccuracy. These evaluation results are shown in Table 3.

TABLE 3 (n = 20) Test device Maintenance accuracy (CV %) 31 2.1 31′ 3.431″ 5.7

As shown in Table 3, when the test solution is transferred to thereagent-maintaining portion, the test solution can be maintainedquantitatively without forming a meniscus, according to the test devicein this example. On the other hand, the test devices 31′ and 31″ wereinferior in maintenance accuracy. The amount of the sample maintained inthe test device 31′ varied probably because of a varying size of themeniscus. The amount of the sample maintained in the test device 31″varied probably because a small amount of the test solution leaked fromthe penetration hole 35″ before the test solution was removed from thesecond hydrophilic region 333″.

Eighth Embodiment

Because the area of the second hydrophilic region is constant, theamount of the test solution maintained in the second hydrophilic regionis approximately determined by its area and the internal diameter of thecapillary tube. However, when the test solution is transferred via thehydrophobic region to the second hydrophilic region, an excess testsolution remains on the hydrophobic region or the first hydrophilicregion. If this excess solution is left, it binds to the test solutionmaintained in the second hydrophilic region, thus lowering analyticalaccuracy.

Accordingly, in the eighth embodiment, an excess liquid-retainer capableof retaining the test solution that may flow from the second hydrophilicregion is formed in the hydrophobic region ranging from the boundaryportion between the hydrophobic region and the second hydrophilic regionto the air outlet. In this embodiment, an excess solution is transientlyretained in the liquid retainer formed in the hydrophobic region.Because this portion is hydrophobic, it repels an excess test solutioninto the air outlet. Accordingly, the test solution can be analyzedhighly accurately. The air outlet is preferably rendered more readilywetted with the test solution than in the hydrophobic region. By doingso, an excess test solution retained in the liquid retainer can berapidly removed into the air outlet. The test device in the eighthembodiment is shown in the plan view of FIG. 19. Hereinafter, the testdevice is described in detail by reference to the drawings.

The test device 41 is provided with the rectangular parallelepiped mainbody 42. The main body 42 is composed of three transparent plates wherethe middle plate is manufactured into a frame, and the hollow 43 whichis long and narrow in the lengthwise direction, surrounded by the frameand the upper and lower plates, acts as a capillary tube. The hollow 43begins at one end of the main body 42 and is blocked on the way withoutreaching the other end. In this example, the beginning portion serves asthe feed opening 44.

The inside of the hollow 43 is composed of the first hydrophilic region431, the hydrophobic region 432 and the second hydrophilic region 433 inthis order from the side of the feed opening 44. The width of the hollow43 from the feed opening 44 to an approximately central region in thehydrophobic region 432 is constant, whereas the width of the hollow 43in the remainder of the hydrophobic region 432 spreads at one side inthe width direction. This spreading portion serves as the liquidretainer 47. The hollow 43 in the second hydrophilic region 433 has thesame width as that of the feed opening 44 and is blocked at its back.

The main body 42 is provided with the penetration hole 45 for permittingthe hydrophobic region 432 communicate with the outside without passingthrough both the hydrophilic regions 431 and 433. The penetration hole45 is connected to the liquid retainer 47 at a portion apart from theboundary between the hydrophobic region 432 and the second hydrophilicregion 433 and extends to the side of the main body 42, so as to beapart from the second hydrophilic region 433. The penetration hole 45functions as an air outlet. A reagent (not shown) is applied to thesecond hydrophilic region 433.

The method of manufacturing the test device 41 is the same as in thefirst embodiment except that two plates made of PS and one plate made ofPVC are used in place of plates made of ABS as the material.

The procedure for analyzing a liquid sample by the test device 41 isalso the same as in the first embodiment.

However, unlike the first embodiment, an excess test solution whichcannot be maintained in the second hydrophilic region 433 is retainedtransiently in the liquid retainer 47. Since the liquid retainer 47 ishydrophobic, the excess solution is immediately repelled by the liquidretainer 47, thus flowing into the penetration hole 45 which is lesshydrophobic than the liquid retainer 47. Accordingly, the amount ofblood to be filled in the second hydrophilic region 433 is always moreconstant than in the first embodiment, and the sample can be analyzedquantitatively with high accuracy.

EXAMPLE 4

The test device 41 in the form shown in FIG. 19 was prepared where thewidth and height of the hollow 43 were 3 mm and 500 μm respectively, andthe depth of the second hydrophilic region 433 was 3 mm.

Human plasma was introduced as the test solution via the feed opening 44into the test device 41, and by applying external forces, the testsolution was transferred to the second hydrophilic region 433. Forcomparison, the test device (not shown) having the same shape andquality as the test device 41 except that it was not provided with theliquid retainer 47 was prepared, and the test solution was transferredto the second hydrophilic region in the same manner. Three minuteslater, the maintained test solution was removed by means of amicro-syringe, and its amount was measured to evaluate the maintenanceaccuracy. These evaluation results are shown in Table 1. The number oftest devices for each case was 20.

TABLE 4 (n = 20) Test device Maintenance accuracy (CV %) 41 1.8Comparative device 3.4

As shown in Table 4, when the test solution is transferred to thereagent-maintaining portion, an excess test solution can be removedrapidly and a suitable amount of the test solution only is maintainedaccording to the test device in this example.

Ninth Embodiment

In the ninth embodiment, an excess test solution which could not bemaintained in the second hydrophilic region is removed in a differentconstitution from that in the eighth embodiment. In this embodiment, theair outlets are formed at a position (first air outlet) close to thefirst hydrophilic region at one side of the capillary tube and at aposition (second air outlet) close to the second hydrophilic region atthe other side of the capillary tube respectively, between which thehydrophobic region is sandwiched. The inside of the capillary tubecommunicates with the air via the first air outlet, so an excess testsolution is rapidly captured by the second air outlet. Accordingly, itcan be analyzed highly accurately. The test device in the ninthembodiment is shown in the plan view of FIG. 20. Hereinafter, the testdevice is described in detail by reference to the drawings.

The test device 51 is provided with the rectangular parallelepiped mainbody 52. The main body 52 is composed of three transparent plates wherethe middle plate is manufactured into a frame, and the hollow 53 whichis long and narrow in the lengthwise direction, surrounded by the frameand the upper and lower plates, acts as a capillary tube. The hollow 53begins at one end of the main body 52 and is blocked on the way withoutreaching the other end. In this example, the beginning portion serves asthe feed opening 54.

The inside of the hollow 53 is composed of the first hydrophilic region531, the hydrophobic region 532 and the second hydrophilic region 533 inthis order from the side of the feed opening 54. The hollow 53 isblocked at the back of the second hydrophilic region 533, and possessesuniform width from the feed opening 54 to the blocked portion.

The main body 52 is provided with the penetration holes 55 and 58 forpermitting the hydrophobic region 532 to communicate with the outsidewithout passing through both the hydrophilic regions 531 and 533. Thesepenetration holes 55 and 58 function as an air outlets. The penetrationholes 55 and 58 are formed at both sides of the capillary tube such thatthey face to each other around the hydrophobic region 532. However, thepenetration hole 55 is close to the second hydrophilic region 533, andthe penetration hole 58 is close to the first hydrophilic region. Theinside of the penetration hole 58 has the same hydrophobicity as thehydrophobic region 532, while the inside of the penetration hole 55 isrendered less hydrophilic than the second hydrophilic region 533 butmore hydrophilic than the hydrophobic region 532. A reagent (not shown)is applied to the second hydrophilic region 533.

The method of manufacturing the test device 51 is the same as in thefirst embodiment except that two plates made of PS and one plate made ofPVC are used in place of plates made of ABS as the material.

The procedure for analyzing a liquid sample by the test device 51 isalso the same in the first embodiment.

However, in the test device 51 unlike the first embodiment, air isintroduced via the penetration hole 58 while an excess test solution isremoved from the penetration hole 55 relatively poor in hydrophobicity.Accordingly, the amount of blood to be filled in the second hydrophilicregion 533 is always more constant than in the first embodiment, and thesample can be analyzed quantitatively with high accuracy.

The second air outlet also functions in capturing an excess testsolution, whereas the first air outlet always fulfills the exhaustfunction only. Accordingly, the inside of the first air outlet ispreferably rendered more hydrophobic than the inside of the second airoutlet in order to raise the reliability of the first air outlet.

EXAMPLE 5

The test device 51 in the form shown in FIG. 20 was prepared where thewidth and height of the hollow 53 were 3 mm and 500 μm respectively, andthe depth of the second hydrophilic region 533 was 3 mm.

Human plasma was introduced as the test solution via the feed opening 54into the test device 51, and by applying external forces, the testsolution was transferred to the second hydrophilic region 533. Forcomparison, the test devices R1, R2 and R3 (not shown) having the sameshape and quality as those of the test device 51 except for thefollowing differences were produced besides the test device 51. The testdevice R1 does not have the penetration hole 58, and further the insideof the penetration hole 55 is rendered hydrophobic to the same degree asin the hydrophobic region 532. In the test device R2, the insides of thepenetration holes 55 and 58 are rendered hydrophobic to the same degreeas in the hydrophobic region 532. In the test device R3, the inside ofthe penetration hole 55 is rendered hydrophobic to the same degree as inthe hydrophobic region 532, while the inside of the penetration hole 58is rendered hydrophilic. In the test devices R1 to R3, the test solutionwas transferred to the second hydrophilic region in the same manner.

When transfer of the test solution was observed, the following threetypes of abnormal transfer occurred besides the normal transfer of asuitable amount of the test solution to be maintained in the secondhydrophilic region. In the first type, the amount of the solutiontransferred to the second hydrophilic region was inadequate as shown inFIG. 21. In the case of the second type, the test solution retained inthe second hydrophilic region contained bubbles as shown in FIG. 22.These problems in both cases were possibly due to an insufficientexhaust function at the time of transfer of the test solution. In thecase of the third type, an excess test solution remained in thehydrophobic region as shown in FIG. 23. The number of test devicesshowing such abnormal transfer is shown for each type in Table. 5.

Three minutes later, the maintained test solution was removed by meansof a micro-syringe, and its amount was measured to evaluate themaintenance accuracy. These evaluation results are collectively shown inTable 5. The number of test devices for each case was 20.

TABLE 5 (n = 20) Maintenance accuracy Test device FIG. 21 FIG. 22 FIG.23 (CV %) R1 2 4 4 4.7 R2 0 3 3 4.0 R3 0 2 2 2.8 41 0 1 0 1.2

As shown in Table 5, when the test solution is transferred to thereagent-maintaining portion, an excess test solution is rapidly removedand a suitable amount of the test solution only is maintained withoutforming bubbles, according to the test device in this example.

Tenth Embodiment

The suction force by capillary action is not strong and readily affectedby the physical properties of the liquid. Accordingly, if the transferof the test solution depends exclusively on capillary action, thetransfer of the test solution to the analytical part is time-consuming.Further, the distance between the test solution feed opening and theanalytical part cannot be made large.

Accordingly, the test device in the tenth embodiment is provided with asuction generating means for promoting transfer of the test solution.FIG. 24 is a perspective view of the test device in the tenthembodiment, and FIG. 25 is an XXV—XXV sectional view of FIG. 24.

The test device 101 is provided with the rectangular parallelepiped mainbody 20, and the main face of the main body 20 is provided with the testsolution feed opening 30, the air hole 40, and the suction generatingchamber 50. The suction generating chamber 50 is arranged so as to beprotruded from the main face of the main body 20, and its inside ishollow. As shown in FIG. 25, the inside of the test device 101 isprovided with the capillary tube 60 leading from the test feed opening30 to the suction generating chamber 50. The capillary tube 60communicates on the way with the air via the air hole 40. Both ends ofthe capillary tube 60 are blocked by the corpuscle removing filter 70 atthe side of the test solution feed opening 30 and by the reagent film 80at the side of the suction generating chamber 50. In the inside of thecapillary tube 60, the analytical part 61 as the first hydrophilicregion, the hydrophobic region 62, and the second hydrophilic region 63are formed linearly from the side of the suction generating chamber 50to the side of the feed opening 30. Said air hole 40 is formed in thehydrophobic region 62.

The materials of the main body 20 make use of light-transmissibleplastics. For example, ABS, polystyrene, polyethylene, polyvinylchloride, polyethylene terephthalate (PET) etc. are used.

The materials of the suction generating chamber 50 should be elastic soas to change the volume of the chamber. The materials which can be usedfor the suction generating chamber 50 include rubber, polyethylene,polyvinyl chloride, PET etc.

The corpuscle removing filter 70 makes use of matrix such as glassfilter to impart liquid permeability and solid impermeability. Lecithinmay be used as filter medium to improve the ability to remove corpusclecomponents.

The reagent film 80 should be gas-permeable and simultaneouslyliquid-impermeable. Accordingly, a porous resin is used as the reagentfilm 80. Further, the reagent film 80 contains a reagent for analyzing aspecific component, as well as an optically reflective agent such astitanium dioxide. Then, the lower half of the reagent film 80 is formedinto the reagent layer 81 containing the reagent, and the upper halfthereof is formed into the optically reflective layer 82 containing anoptically reflective agent. However, the reagent and the opticallyreflective agent may be mixed.

The method of forming the analytical part 61 (first hydrophilic region),the hydrophobic region 62, and the second hydrophilic region 63 in theinside of the capillary tube 60 is essentially the same as in the firstembodiment.

Analysis of plasma or serum components by the test device 101 is asfollows.

First, after whole blood is applied onto the feed opening 30, thesuction generating chamber 50 is pressed with a finger whereby itsvolume is reduced, and simultaneously the excess air therein is removedfrom the air hole 40. Then, the air hole 40 is closed with anotherfinger, and the finger pressing against the suction generating chamber50 is removed. The suction generating chamber 50 is composed of anelastic material so that the reduced volume will return to the originalvolume. Suction is thereby generated, and the whole blood in the feedopening 30 is introduced into the capillary tube 60, to transfer to theanalytical part 61. However, the corpuscle removing filter 70 allows theliquid to pass but does not allow solids to pass therethrough, so thecorpuscle components are removed and only plasma or serum is introducedinto the capillary tube 60, to transfer to the analytical part 61.Because this filter is arranged apart from the analytical part, there isno need to worry about errors due to the influence of corpusclecomponents in order to optically measure the result of reaction with thereagent.

Then, the finger with which the air hole 40 is closed is removed andleft for a while. By doing so, a predetermined amount of plasma or serumcan be fed to the analytical part 61. That is, the analytical part 61 ishydrophilic, and it is surrounded by the hydrophobic region 62 and theair-permeable but liquid-impermeable reagent film 80, so the amount ofplasma or serum fed to the analytical part 61 is always equal to thevolume of the analytical part 61. However, because the suction force ofthe suction generating chamber 50 is relatively strong where the abilityof the hydrophobic region 62 to repel water is inadequate, excess plasmaor serum may remain in the hydrophobic region 62. In this case, the testdevice 101 is e.g. slightly shaken with the hand so that the excessplasma or serum may be returned to the second hydrophilic region 63. Ifthere is air in the capillary tube 60, the air is simultaneously removedfrom the air hole 40.

If plasma or serum is fed to the analytical part 61, the reagentcontained in the reagent film 80 is eluted. As a result of its reactionwith a specific component in plasma or serum, a colored substance isformed and the plasma or serum is thereby colored. The main body 20 islight-transmissible, and the reagent film 80 has the opticallyreflective layer 82, so the degree of this coloration can be measuredwith a device equipped with light irradiation part 90 and lightdetecting part 10, such as densitometer.

The test device 101 can generate strong suction in the capillary tube bythe suction generating means in addition to capillary action, and thisforcible suction can be utilized to transfer the test solution forciblyfrom the feed opening for the test solution to the analytical part.

Accordingly, unlike a test device using only capillary action, a testsolution containing corpuscles such as whole blood which requirefiltration can also be measured by the present test device, and the testsolution can be rapidly transferred. Further, even a test solutionobtained in such a small volume as the volume of the analytical part canbe subjected to measurement. That is, regardless of the amount orphysical properties, the test solution can be certainly transferred tothe analytical part.

Eleventh Embodiment

As the eleventh embodiment, the test device 101 including a rollerautomatically regulating the volume of the suction generating chamberand opening and shutting the air hole is shown in FIG. 26. FIG. 26 showsthe test device at each stage for analysis of plasma or serumcomponents. FIG. 26(A), FIG. 26(B), and FIG. 26(C) are sectional viewsof the test device 11 at the preparative stage, corpuscle removing stageand plasma or serum volume regulating stage.

At the preparative stage (A), roller 140 presses the suction generatingchamber 50 downward to reduce the volume. At the stage of (B), roller140 rolls down from the suction generating chamber 50 and stops on theair hole 40, thereby shutting the passage of air. The volume of thesuction generating chamber 50 will be returned to the original volume,thus generating suction. Corpuscles are thereby removed from whole blood150, and plasma or serum 160 is introduced into the capillary tube. Atthe stage of (C), roller 140 rolls again whereby the air hole 40 isopened. At this stage, the amount of plasma or serum fed to theanalytical part is regulated.

Because roller 140 automatically works, it is not necessary for theoperator to press the suction generating chamber 50 or to close the airhole 40 by the finger. Accordingly, the procedure is made simpler, andan operational miss by the operator can be prevented.

In the tenth and eleventh embodiments, the reagent film 80 contains areagent, but the reagent may replaced by the air-permeable butliquid-impermeable film and the reagent may be directly applied onto thesurface of its facing analytical part 61, i.e. onto the surface of thefirst hydrophilic region in order to fix the reagent thereto.

Industrial Applicability

According to the test device of the present invention, a test solutioncan be analyzed by applying a suitable amount of a test solution withoutpreviously measuring the test solution by a measuring device.Accordingly, it is useful as an analytical device for rapid and easyanalysis. Further, the test device of the preset invention can beproduced in a less number of steps because a reagent can be fixed bymerely applying the reagent onto a predetermined position.

What is claimed is:
 1. A test device for analyzing a specific componentin a test solution with a reagent by allowing the test solutionintroduced via a test solution feed opening to react with the reagentmaintained in a predetermined position in a capillary tube having thefeed opening and an air outlet, said test device comprising: agas-permeable, liquid-impermeable film blocking an end at the oppositeside of the feed opening; and suction generating means for generatingsuction in the capillary tube via said film, said capillary tubecomprising: a first hydrophilic region for transferring the testsolution from the test solution feed opening to the reagent; a secondhydrophilic region having a predetermined area maintaining the reagent;and a hydrophobic region which separates the first hydrophilic regionfrom the second hydrophilic region and communicates with the air outletwithout passing through the first and second hydrophilic regions.
 2. Thetest device according to claim 1, wherein the film contains the reagent.3. The test device according to claim 1, wherein the feed opening isblocked with a liquid-permeable, solid-impermeable filter.
 4. The testdevice according to claim 1, wherein the suction generating means is asuction generating chamber the volume of which is changeable.